Jean-Francois Aubry, Oscar Bates, Christian Boehm, Kim Butts Pauly, Douglas Christensen, Carlos Cueto, Pierre Gelat, Lluis Guasch, Jiri Jaros, Yun Jing, Rebecca Jones, Ningrui Li, Patrick Marty, Hazael Montanaro, Esra Neufeld, Samuel Pichardo, Gianmarco Pinton, Aki Pulkkinen, Antonio Stanziola, Axel Thielscher, Bradley Treeby, and Elwin van 't Wout, Journal of the Acoustical Society of America 2022, Volume 152, Issue 2, Article No. 1003, online 16 August 2022; doi: 10.1121/10.0013426
Computational models of acoustic wave propagation are frequently used in transcranial ultrasound therapy, for example, to calculate the intracranial pressure ﬁeld or to calculate phase delays to correct for skull distortions. To allow intercomparison between the different modeling tools and techniques used by the community, an international working group was convened to formulate a set of numerical benchmarks. In the published study, 9 different benchmarks of increasing geometric complexity are presented and deﬁned, along with intercomparison results. The benchmarks include a single-layer planar bone immersed in water, a multi-layer bone, and a whole skull. Two transducer conﬁgurations — a focused bowl and a plane piston operating at 500 kHz — are considered, giving a total of 18 benchmark permutations. Eleven different modeling tools were used to compute the benchmark results. The models span a wide range of numerical techniques, including the ﬁnite-difference time-domain, angular spectrum, pseudospectral, boundary-element, and spectral-element methods. Good agreement is found between the models, particularly for the therapeutically relevant position, size, and magnitude of the acoustic focus within the skull. Cross-comparison of the results for each model with every other model indicates that the median values for each benchmark for the difference in focal pressure and position were found to be below 10% and 1 mm, respectively. The benchmark deﬁnitions, model results, and intercomparison codes are freely available to facilitate further comparisons and verification of 3rd-party modeling tools.
The scientific and technical impact of the study can be summarized as: